The present invention relates to material handling equipment, and, more particularly to an apparatus and method for releasably securing a material handling tool to an arm, such as a dipper boom of a backhoe or loader lift arms of a front loader.
The changing of material handling tools such as buckets, blades, rippers, augers, etc., mounted on an arm such as a dipper boom of a backhoe, has traditionally been difficult and time consuming. In addition, various tools, such as wrenches and hammers, are required to change such material handling tools. In some situations, the changing of a material handling tools requires two people.
A conventional device for mounting a bucket to a backhoe dipper boom includes a pair of coaxial, axially-spaced bores in the bucket and a pair of cylindrical coaxial bosses on the dipper boom that are aligned with the bores in the bucket. Hinge pins extending through the bores and bosses retain the bucket on the boom. U.S. Pat. No. 4,127,203, issued on Nov. 28, 1978, discloses such a mounting device. A disadvantage of such a device is that precise alignment is required between the bores and bosses in order for the hinge pins to be inserted. Furthermore, once the pins are inserted, any forces exerted between the bucket and the boom can cause jamming of the pins. Specifically, it is a common problem in older machines for "hydraulic creep" in the dipper boom to create a downward pressure on the bucket, thus resulting in a binding of the pins.
U.S. Pat. Nos. 3,934,738 and 4,311,428 disclose bucket attachment devices that include a main body connected to a dipper boom. At the forward end of the main body is a hook that engages within a specially designed opening in the bucket. At the rearward end of the main body is a receptacle for receiving a projection extending from the bucket. When the bucket is in place with respect to the main body, a pin may be inserted through the bucket projection and main body receptacle to lock the bucket to the main body. Disadvantages of this system include the fact that the pin may become jammed or lost, and that tools may be required to remove or insert the pin.
U.S. Pat. Nos. 3,606,052 and 4,187,050 disclose quick-disconnect coupling devices for attaching a bucket to a dipper boom. These devices each incorporate a dipper boom attachment that includes a pivoting latch plate that engages with a pin on the bucket to secure the bucket to the dipper boom. Disadvantages of these systems include the fact that the attachment means on the bucket must be specifically sized to the attachment means on the dipper boom, thus reducing versatility of the system.
In fact, it is a common disadvantage of many of the prior art attachment systems that the portion of the system that attaches to the dipper boom is specifically sized to a particular model bucket. For example, the size and location of the pins on the bucket must conform to the attachment device mounted to the dipper boom. Thus, if a backhoe operator wanted to change buckets, it is likely that the attachment device on the dipper boom would likewise need to be replaced. Not only is it typical for a manufacturer to make material handling tools of several different sizes that are not compatible with the same attachment device, but the attachment devices made by one manufacturer are frequently not compatible with material handling tools made by a different manufacturer.
It is a further disadvantage of many of the prior art systems that a portion of the attachment system is integrally connected to either the bucket or the dipper boom. Thus, in the event of a failure of that portion of the system, the entire equipment must be inoperable while the failed portion is repaired.